Intraocular implant, delivery device, and method of implantation

ABSTRACT

An ophthalmic implant for treatment of glaucoma, a delivery device for implanting such an implant, and a method of implanting such an implant. The implant includes a tube having an inlet end, an outlet end, and a tube passage therebetween, and a disk connected to the tube at the outlet end of the tube. The tube passage has a cross-sectional area sufficiently small to inhibit the flow of aqueous humor through the tube passage. The implant provides a bleb of aqueous humor under the conjunctiva so that the bleb and the elasticity of the conjunctiva assist in regulating the flow of aqueous humor through the tube as a function of the IOP. The tube at its inlet end has a beveled surface facing away from the iris and one or more circumferential holes. One or more retention projections are provided for anchoring and may be extended outwardly when the implant is implanted in the eyeball. The disk has an outer rim and one or more inner uprights. The implant is implanted by use of a delivery device comprising a handle and a rodlike instrument, with a tip for insertion into the tube passage of the implant and a retention mechanism for retaining the implant. During implantation, the implant is inserted through a slit in a portion of the conjunctiva which normally lies at a distance away from the intended implantation site.

FIELD OF THE INVENTION

[0001] The invention relates generally to ophthalmic implants fortreatment of glaucoma, delivery devices for implanting such implants,and to methods of implanting such implants.

BACKGROUND OF THE INVENTION

[0002] Glaucoma is an eye condition characterized by an increase in theintraocular pressure (IOP) of the eye to an abnormal level. A normal eyemaintains a proper IOP by the circulation within the eye of aqueoushumor aqueous humor is secreted from the ciliary body, passes throughthe pupil into the anterior chamber of the eyeball, and is filtered outof the eyeball via the trabeculum and the Canal of Schlemm. Withglaucoma, the aqueous humor excretory pathway is blocked, the aqueoushumor cannot pass out of the eyeball at an adequate rate, the IOP rises,the eyeball becomes harder, and the optic nerve atrophies by thepressure applied on its fibers leaving the retina. A characteristicoptic neuropathy develops, resulting in progressive death of theganglion cells in the retina, restriction of the visual field, andeventual blindness. Advanced stages of the disease are characterizedalso by significant pain.

[0003] Glaucoma treatment, it initiated early in the course of thedisease, can prevent further deterioration and preserve most of theocular functions. The goal of glaucoma treatment is to reduce the IOP tolevel which is considered safe for a particular eye, but which is not solow as to cause ocular malfunction or retinal complications.

[0004] One type of glaucoma treatment is filtration surgery, whichprovides an alternate route for aqueous humor to exit the anteriorchamber of the eyeball and enter the sub-conjunctival space, therebylowering the IOP. In full thickness operations a fistula is createdthrough the limbal sclera, connecting directly the anterior chamber ofthe eyeball and the sub-conjunctival space. Full thickness operationsprovide long-lasting control of IOP; however, excessive loss of aqueoushumor from the eyeball during the early postoperative period frequentlyleads to hypotony.

[0005] In guarded filtration surgery (trabeculectomy), a fistula createdthrough the limbal sclera is protected by an overlying partial thicknesssutured scleral flap. The scleral flap provides additional resistance toexcessive loss of aqueous humor from the eyeball, thereby reducing therisk of early postoperative hypotony. However, trabeculectomy may resultin higher eventual IOP and increased risk of late failure of filtration,compared with full thickness operations.

[0006] In accordance with one recently introduced procedure, a fullthickness filtering fistula may be created by a holmium laser probe,with minimal surgically induced trauma. After retrobulbar anesthesia, aconjunctival incision (approximately 1 mm) is made about 12-15 mmposterior to the intended sclerostomy site, and a laser probe isadvanced through the sub-conjunctival space to the limbus. Then,multiple laser pulses are applied until a full thickness fistula iscreated. This technique has sometimes resulted in early hypocony onaccount of a difficulty in controlling the sclerostomy size. Inaddition, early and late iris prolapse into the sclerostomy has resultedin abrupt closure of the fistula and eventual surgical failure. Further,despite its relative simplicity, the technique still necessitates theuse of retrobulbar anesthesia to avoid pain caused by the laserapplications. The injection of anesthetic material close to the alreadydamaged optic nerve may sometimes lead to further visual damage. Afurther disadvantage of this procedure, as well as other types ofglaucoma filtration surgery, is the propensity of the fistula to besealed by scarring.

[0007] Various attempts have been made to overcome the problems offiltration surgery, for example, by using ophthalmic implant devices.Typical ophthalmic implants utilize drainage tubes so as to maintain theintegrity of the openings formed in the eyeball for the relief of theIOP.

[0008] Typical ophthalmic implants suffer from several disadvantages.For example, the implants typically utilize a valve mechanism forregulating the flow of aqueous humor from the eyeball; defects in and/orfailure of such valve mechanisms could lead to excessive loss of aqueoushumor from the eyeball and possible hypotony. The implants also tend toclog over time, either from the inside by tissue, such as the iris,being sucked into the inlet, or from the outside by the proliferation ofcells, for example by scarring. Additionally, the typical implantinsertion operation is complicated, costly and takes a long time.

[0009] U.S. Pat. No. 3,788,327 to Donowitz et al. shows a prior artimplant utilizing a valve mechanism for regulating the flow of aqueoushumor from the eyeball. As stated above, defects in and/or failure ofsuch a valve mechanism could lead to excessive loss of aqueous humorfrom the eyeball and possible hypotony. Additionally, both the inletopening and the outlet opening in the implant shown in U.S. Pat. No.3,788,327 may be susceptible to clogging—the inlet opening by the irisand the outlet opening by scarring. Finally, implantation of an implantaccording to U.S. Pat. No. 3,788,327 may involve the separate steps offirst providing a tract for receiving the implant and/or suturing theimplant once it is in place, which add time and possible complicationsto the operation.

SUMMARY OF THE INVENTION

[0010] It is an object of the invention to provide an improvedophthalmic implant which may be implanted into the eyeball for thetreatment of glaucoma, a delivery device for implanting such an implant,and an improved method of implanting such an implant into the eyeball.

[0011] In one embodiment of an improved implant in accordance with theinvention, an intraocular implant is provided to be implanted in theeyeball. The implant includes a tube having an inlet end, an outlet end,and a tube passage therebetween for permitting aqueous humor to flow outof the eyeball, and a flanged disk connected to the tube at the outletend of the cube. The cube passage has a cross-sectional areasufficiently small to inhibit the flow of aqueous humor through the tubepassage when the IOP is below a threshold amount, thereby preventing theIOP from falling below its critical limit.

[0012] The flanged disk, which is designed to be located underneath theconjunctiva, may have an outer rim for forming a reservoir having anenlarged cross-sectional area relative to the cross-sectional area ofthe tube passage. When the IOP is above the threshold amount such thataqueous humor is able to flow through the tube passage, the elasticityof the conjunctiva in conjunction with this design of the flanged diskassists in regulating the flow of aqueous humor through the tube as afunction of the IOP.

[0013] To prevent clogging of the implant, the tube at its inlet end maybe provided with a beveled surface which faces away from the iris whenthe implant is inserted. Additionally, one or more circumferential holesmay be provided along the tube for allowing aqueous humor to flow intothe tube passage even if the axial inlet opening is blocked.

[0014] To prevent clogging at the outlet end, the flanged disk may havean outer rim as described above which raises the conjunctiva away fromthe axial outlet of the tube passage to allow outflow. One or more inneruprights (which may be in the form of an inner rim) may also be providedon the flanged disk for this purpose. Clogging is further avoided byimplanting the implant under the conjunctiva at a distance away from aninsertion slit in the conjunctiva, such that healing of the slit doesnot cause scar tissue to form in the area of the axial outlet opening ofthe implant.

[0015] Implantation may be facilitated by further features of theimplant. For example, the implant may have one or more retentionprojections (for example, in the form of a spur, flange, or plate). Theretention projection may be rigid, or it may be made of an elasticmaterial such that it is able to be flexed inward against the tubeduring penetration through the sclera. Alternatively, the retentionprojection may be designed to lie initially relatively flat against thetube for easier penetration through the sclera and to prevent tearing ofthe sclera, with a mechanism for extending the retention projectionoutwardly when the implant is implanted in the eyeball. For example, theretention projection may be extended outwardly by a separate expansiontool or may be constructed of a shape memory alloy so that it isextended outwardly when subjected to the heat of the eyeball. One ormore retention projections according to the invention are sufficient toreliably anchor the implant in the eyeball without the need for sutures,saving time and costs.

[0016] Implantation may also be facilitated by the provision of one ormore markers on the implant visible through the cornea upon passingthrough the sclera. For example, a circumferential hole as describedabove may serve as a marker; alternatively, the marker may be some othersuitable visible mechanism, such as a scratch or colored mark on thecube. The visibility of the marker lets the doctor know that the markerhas passed through the sclera, indicating that the implant is in place.

[0017] Implantation of an implant may be performed by use of a deliverydevice in accordance with the invention, comprising a handle and arodlike instrument, for example a needle or probe, for carrying theimplant for insertion into the eyeball. The delivery device has a tipfor insertion into the tube passage of the implant and a suitableretention mechanism for preventing the implant from moving up thedelivery device during implantation. The retention mechanism may also beconstructed to prevent the implant from rotating during implantation toinsure proper orientation of the implant in the eyeball. The deliverydevice may additionally have a suitable expansion tool for extending oneor more retention projections of the implant outwardly once theprojection or projections have penetrated through the sclera.

[0018] In one embodiment of an improved method of implanting an implantaccording to the invention, a small slit is cut in a portion of theconjunctiva which normally lies at a distance away from the intendedimplantation site. As the implant itself is very small, the slit alsomay be very small, for example about 2 mm in length or less. The smallsize of the slit as well as its positioning at a distance away from theimplantation site, for example about 10 mm, helps prevent contaminationof the sclerostomy site and reduces the risk of infection.

[0019] The implant is placed through the slit, directed to theimplantation site, and inserted into the sclera at the implantationsite. The sclera may be pierced either by a needle-like tip of the tubeof the implant formed by a beveled surface at the inlet end of the tubeas described above or by the tip of a needle of the delivery devicewhich carries the implant. Thus, the implant may be inserted directlyinto the eyeball without the need for any separate piercing step,resulting in cost and time savings.

[0020] An intraocular implant, delivery device, and method ofimplantation according to the invention provide the advantages of a fullthickness fistula, while avoiding the limitations of the standardtrabeculectomy. An implant according to the invention may be very smalland implantable without surgery. No surgery room or hospitalization isnecessary, thereby reducing costs. Implantation is minimally invasive,simple and quick, requiring only local anesthesia. Retrobulbaranaesthesia is not necessary, and thus iatrogenic damage to the opticnerve is avoided There is no need to perform an iridectomy, and thusaqueous flow is maintained, lens nourishment is unaffected, and thelikelihood of cataracts developing as a result of the procedure isreduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a schematic cross-sectional view of a first embodimentof an intraocular implant according to the invention, shown inserted inan eyeball;

[0022]FIG. 2 is an enlarged perspective view of the intraocular implantof FIG. 1;

[0023]FIG. 3 is a view similar to FIG. 2, with part of the intraocularimplant cut away to show a sectional view thereof;

[0024]FIG. 4 is an enlarged perspective view of a disk portion of theintraocular implant of FIG. 1;

[0025]FIGS. 5 through 7 illustrate the action of the conjunctiva duringoperation of the incraocular implant of FIG. 1;

[0026]FIGS. 8 through 10 illustrate a delivery device and insertion ofthe intraocular implant of FIG. 1 into an eyeball;

[0027]FIG. 11 is an enlarged perspective view of a second embodiment ofan intraocular implant according to the invention, with part of theintraocular implant cut away to show a sectional view thereof;

[0028]FIG. 12 is a cop view of the incraocular implant of FIG. 11,showing a flanged disk portion of the implant;

[0029]FIG. 13 illustrates a delivery device and insertion of theintraocular implant of FIG. 11 into an eyeball;

[0030]FIG. 14 is a schematic cross-sectional view of the intraocularimplant of FIG. 11, shown inserted in an eyeball; and

[0031]FIGS. 15 and 16 illustrate a third embodiment of an intraocularimplant according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 illustrates an intraocular implant 30, constructed inaccordance with an embodiment of the invention, implanted in an eyeball10. The implant 30 comprises a needle-like tube 32 and a flanged disk34. The plane of the flanged disk 34 forms an angle with the tube 32chat corresponds to the angle between the surface of the sclera 12 andthe axis of insertion of the implant 30. The implant 30 is inserted inthe sclera 12 of the eyeball 10, in the limbal area 14 adjacent to thecornea 16, and protrudes into the anterior chamber 20 adjacent the iris22. The implant 30 is inserted so that the flanged disk 34 is placed ona surface of the sclera 12 underneath the conjunctiva 18. The implant 30may be placed above or below the Tenon's capsule (not shown) It will beappreciated by persons of ordinary skill in the art that the exactlocation for inserting the implant 30 is not restricted to that shown,and may be any other suitable position, such as behind the iris 22.

[0033]FIG. 2 shows an enlarged perspective view of the implant 30 ofFIG. 1, and FIG. 3 shows a similar view, with part of the implant 30 cutaway. The tube 32, which may take the form of a modified standardretrobulbar tip, has an inlet end 40, an outlet end 50, and a tubepassage 38 extending therebetween, with the tube passage 38 having anaxial inlet 41 and an axial outlet 51. The flanged disk 34 is connectedto the tube 32 at its outlet end 50. The entire implant is very small;for example the cube 32 may have a length of about 2 mm and a width ofabout 0.5 mm, and the flanged disk 34 may have a diameter of about 1 mmand a thickness of less that 0.1 mm.

[0034] The tube passage 38 has a cross-sectional area sufficiently smallto inhibit the flow of aqueous humor through the cube passage when theIOP of the eye is below a threshold amount, thereby preventing the IOPfrom falling below its critical limit. In one embodiment, for example,the cylindrical tube passage 38 has a diameter of 300 micrometers, suchthat an IOP of 5 mm Hg is needed for the aqueous humor to flow out.Thus, by using a specified internal cross-sectional area for the tubepassage, excessive loss of aqueous humor from the eyeball is prevented.

[0035] When the IOP is above the threshold amount, aqueous humor drainsfrom the anterior chamber 20 of the eyeball 10 through the axial inlet41 and one or more circumferential holes 72, through the tube passage38, and into the space under the conjunctiva 18. The circumferentialholes 42 may take any suitable form; for example, they may be in theform of circular openings whose combined cross-sectional area is equalto the cross-sectional area of the tube passage 38. The circumferentialholes 42 prevent the tube passage 38 from becoming clogged at its inletend because, even if the iris 22 obstructs the axial inlet 41, aqueoushumor can still pass through the circumferential holes 42. In the eventthe axial inlet 41 is obstructed, the circumferential holes 42 alsoserve to cause a back pressure in the tube passage 38 to unclog theaxial inlet 41. The circumferential holes 42 serve the additionalpurpose of insuring a proper insertion depth of the implant 30, as theupper hole is visible during implantation after penetration through thesclera and thus can be used as a marker. To serve this function, anyother suitable marker (such as a scratch or colored mark) may be used.

[0036] The inlet end 40 of the tube 32 has a needle-like tip formed by abeveled surface 36, angled sharply for easy insertion into the eyeball.The beveled surface 36 increases the area of the axial inlet 41 toenlarge the entrance to the tube passage 38. The beveled surface 36 isdesigned to face away from the iris 22 to reduce the possibility ofobstruction of the axial inlet 41. Because the flanged disk 34 isdesigned to rest against the sclera 14 and the beveled surface 36 isdesigned to face away from the iris 22, the beveled-surface 36 lies in aplane which is angled opposite to the plane in which the flanged disk 34lies.

[0037] The tube 32 may have one or more retention projections in theform of one or more spurs 52 provided integrally with it for retainingthe implant 30 in the eyeball 10 after insertion. Alternatively, theretention spur 52 may be made as a separate part connected to the tube32 by, for example, welding or brazing. The retention spur 52 may berigid, or it may be flexible such chat it bends coward the tube 32during penetration of the sclera and springs outward to its originalshape after passing through the sclera. Alternatively, the retentionsour 52 may be designed for plastic deformation by a separate expansiontool (for example, a balloon) once it is in the eyeball 10, or theretention spur 52 may be constructed of a shape memory alloy such thatthe spur is flat against the tube when cool but expands to its finalshape when subjected to the heat of the eyeball 10.

[0038] The flanged disk 34, shown enlarged in FIG. 4, comprises a base44, an outer rim 46, and a plurality of inner uprights 48. The base 44and outer rim 46 define a reservoir 54 such that, in operation, theaqueous humor flows out of the axial outlet 51 of the tube passage 38,between the uprights 48, and into the reservoir 54. The enlargedcross-sectional area of the reservoir 54 as compared to thecross-sectional area of the tube passage 38 provides a larger area forabsorption of the aqueous humor by the conjunctiva 18 and also acts inconjunction with the elasticity of the conjunctiva 18 to assist inregulating the flow of aqueous humor through the implant 30 as afunction of the IOP.

[0039]FIGS. 5 through 7 illustrate the action of the conjunctiva 18during operation of the implant 30, in which it can be seen that theaqueous humor which flows out of the tube passage forms a “bleb” 24below the conjunctiva 18. It will be appreciated by persons havingordinary skill in the art that a higher IOP results in a higher flowrate through the implant 30, and a greater force of the aqueous humor onthe conjunctiva 18.

[0040] In addition to defining the reservoir 54, the outer rim 46 of theflanged disk 34 serves the additional purpose of raising the conjunctiva18 away from the axial outlet 51 to prevent clogging of the tube passage38. The inner uprights 48 also serve this purpose.

[0041] The shape of the flanged disk 34 may be, but is not limited to,an ellipse, and it will be appreciated by persons having ordinary skillin the art that it may conform to any shape which allows the implant tofit under the conjunctiva 18 and which regulates the IOP. The sizeand/or shape of the flanged disk 34 and/or the angle between the flangeddisk 34 and the tube 32 can also be changed in order to use differentimplants for different persons' eyes.

[0042]FIGS. 8 through 10 illustrate a delivery device 60 and a method ofinserting the intraocular implant 30 into an eyeball. The implant 30 isfirst attached to the delivery device 60, having a handle 62 and asuitable rodlike instrument 64 such as a needle or probe. The rodlikeinstrument 64 has a tip 70 for penetrating a tube passage of the implant30 and a retention mechanism for preventing the implant from moving upthe delivery device during implantation, for example in the form of anabutment surface 68 having an angle generally corresponding to that ofthe flanged disk 34. This configuration also prevents rotation of theimplant 30 on the delivery device 60, thereby insuring properorientation of the implant in the eyeball. The retention mechanism mayalso include one or more projections for extending inside the outer rimand/or between the inner uprights on the flanged disk 34. In analternative embodiment, the retention mechanism may be the tip of therodlike instrument, constructed to engage the inside of the tube passageof the implant with a friction fit, thereby preventing the implant frommoving up the delivery device during implantation.

[0043] A delivery device 60 in which the rodlike instrument is a needle65 is illustrated in FIG. 9. In that illustrated embodiment, thedelivery device 60 is similar to a standard medical syringe having ahousing and a needle 65 with a bore 67. The front tip 69 of the needle65 is configured as an abutment surface having an angle generallycorresponding to that of the flanged disk 34. The bore 67 of the needle65 has a tip in the form of a plug 71 which is configured to have across-sectional shape corresponding to that of the tube passage 38. Theimplant 30 is placed over the plug 71, with the end of the plug 71projecting into the tube passage 38, and with the front tip 69 of theneedle 65 abutting against the flanged disk 34. The plug 71 blocks thetube passage 38 during implantation.

[0044] To insert the implant 30 into the eyeball 10, a small slit 26 iscut in a portion of the conjunctiva 18 which normally lies at a distanceaway from a portion 28 of the conjunctiva 18 which normally covers theintended implantation site. A small slit distanced away from theimplantation site, for example a 1-2 mm slit about 5-15 mm away from theimplantation site, reduces the possibility of aqueous humor flowing outof the conjunctiva through the slit, reduces the possibility ofinfection, reduces the possibility of scarring over the axial outlet ofthe implant, and facilitates closing and healing.

[0045] The implant 30, by delivery device 60, is passed through the slit26, under the conjunctiva 18, to the implantation site in the sclera 14.FIG. 9 shows the advancement of the implant only schematically; it willbe appreciated that in practice the implant is directed from the slit tothe implantation site generally along the surface of the sclera, suchthat the longitudinal axis of the implant is generally parallel to thesurface of the sclera. Upon reaching the implantation site, the implantis tilted for penetration into the sclera The acute angle of theneedle-like tip formed by the beveled surface 36 of the implant 30ensures that the implant 30 enters the sclera 14 easily. The needle-liketip penetrates through the sclera 14 into the anterior chamber 20 of theeyeball 10, while the flanged disk 34 is pushed up against the sclera14.

[0046] When the implant 30 is in place, as shown in FIG. 10, theretention spur (or spurs) 52 anchors the implant 30 in the eyeball 10and prevents the implant 30 from sliding out as the delivery device 60is withdrawn. The retention spur 52 also prevents the implant 30 fromslipping out once in place.

[0047] It will be appreciated by persons having ordinary skill in theart that the insertion of the implant is not restricted to the methoddescribed above, and it may be inserted by any of several methods knownin the art. The delivery device may comprise an ‘internal’ or ‘external’needle. A straight or twisted guide wire, known in the art, may also beused to guide the delivery device to its precise position. To easeinsertion, the delivery device may be vibrated, or a lubricant, such asmedical paste or gel, can be spread onto the delivery device.Additionally, after implantation of the implant a suitable fibrosisinhibiting compound (e.g. 5FU, mitomycin) may be applied to theimplantation site.

[0048]FIG. 11 shows an alternative embodiment of an intraocular implant130 constructed in accordance with the invention. The implant 130comprises a tube 132 attached to an elliptical flanged disk 134. Thetube 132 has an inlet end 140, an outlet end 150, and a tube passage138, with the tube passage 138 having an axial inlet 141, an axialoutlet 151, and circumferential holes 142 to drain the aqueous humorfrom the anterior chamber 20 of the eyeball 10 into the space under theconjunctiva 18.

[0049] The distal end 152 of the tube 132 has a partially conical shape.A plurality of retention projections in the form of retention flanges158 are formed on the outer circumference of the tube 132, approximatelyparallel to the flanged disk 134, to act as anchors to retain theimplant 130 in the eyeball.

[0050] As shown in the enlarged view in FIG. 12, the flanged disk 134comprises an elliptical base 144, an outer rim 146, and an inner uprightcurved to form an inner rim 148, defining therebetween a reservoir 154.A plurality of “U”-shaped passageways 156 are formed in the inner rim148 for allowing aqueous humor to flow from the axial outlet 151 intothe reservoir 154. The outer rim 146 and the inner rim 148 prevent theconjunctiva 18 from clogging the axial outlet 151.

[0051] As shown in FIG. 12, the flanged disk 134 is elliptical in shape.The longer axis of the flanged disk 134 is approximately twice thediameter of the tube 132, and the flanged disk 134 is eccentricallydisplaced relative to the tube 132. The elliptical shape and placementof the flanged disk 134 allows a wide anchoring area for the implant 130and maximizes the outlet drainage area on the longer axis of theellipse. The shorter axis of the ellipse enables the implant 130 to fitwithin the narrow space under the conjunctiva 18.

[0052]FIG. 13 illustrates a delivery device 160 and a method ofinserting the intraocular implant 130 into an eyeball. The implant 130is slidably fixed over a needle 164 of the delivery device 160, which,similar to a standard medical syringe, has needle 164 attached to ahousing 162. The tip 174 of needle 164, which passes through the implant130, is acutely angled so that the tip 174 is generally in line with theangle of the lower part the implant 130.

[0053] A front surface of the delivery device 160 is formed as anabutment surface angled to match the angle of the flanged disk 134 andfurther comprises an indent 172 to hold the implant 130 in place duringimplantation. The shape of the delivery device 160 and the angledsurface of the flanged disk 134 prevent the implant 130 from rotatingduring implantation.

[0054] The delivery device 160 shown in FIG. 13 is used in a mannersimilar to that described above with reference to FIGS. 8 through 10. Inthis embodiment, however, the acute angle of the needle tip 174 piercesthe sclera. The angled inlet end of the implant device 130 follows theneedle tip 174 through the sclera 14, into the anterior chamber 20 ofthe eyeball. As shown in FIG. 14, the retention flanges 158 anchor theimplant 130 in position and prevent the implant 130 from sliding out asthe delivery device 160 is withdrawn. The anchorage of the retentionflanges 158 also prevents the implant 130 from slipping out once inplace

[0055]FIGS. 15 and 16 illustrate a third embodiment of an intraocularimplant according to the invention. This embodiment is similar to thatshown in FIGS. 1 through 10, with the exception that a separatelyattached retention projection in the form of a retention plate 252 isused for anchoring instead of the retention spur 52. The retention plateis inserted into a groove 253 in the tube of the implant 230 and may befastened by any suitable means, for example by welding in the case of animplant 230 constructed of stainless steel.

[0056] An intraocular implant constructed in accordance with theinvention may be manufactured entirely from or covered with any suitablematerial such as stainless steel, silicon, gold, nitinol, Teflon,tantalum, PMMA, or any other suitable plastic or other material. Theimplant may also be coated with heparin or any other suitable biologyactive compound.

[0057] Manufacture of an intraocular implant in accordance with theinvention may be carried out according to the following process. Thetube may be formed from the tip of a standard stainless steel hypodermicneedle. Using an EDM machine, small holes are drilled proximate the tipof the needle to form the circumferential holes. At a distance from thetip corresponding to the desired length of the tube, the needle is cutat the appropriate angle to correspond to the desired angle of theflanged disk The side of the needle is then undercut to form aprojection which can be later bent outwardly to form the sour.

[0058] The disk may be chemically etched from a stainless steel sheetaccording to the following process. A pattern of the disk is drawn on acomputer aided design (CAD) system and plotted on a transparent filmusing a laser plotter. Plottings are made of both the upper side and thelower side of the disk. The plotting for the upper side, for example,includes the outer rim and the inner uprights; the plotting for thelower side, for example, includes the base of the disk.

[0059] A layer of photoresist is adhered to both surfaces of thestainless steel sheet. The photoresist is then exposed to UV lightthrough the film on which the plottings are made. The areas of the sheetwhich are blocked by the plottings are not exposed. The photoresistwhich has been exposed to UV light is then chemically removed.

[0060] Using an etching chemical, the stainless steel sheet is thenetched, so that the chemical eats away the areas of the sheet from whichthe photoresist has been removed. The etching is time-controlled suchthat the chemical only takes away material to a predetermined depth.

[0061] By use of a plotting for the upper side which includes the outerrim and the uprights, the chemical on the upper surface of the sheettakes away material on the outside of the disk, in the reservoirincluding between the uprights, and in the center of the disk which isto receive the tube. Because the etching is time-controlled, thechemical acting on the top of the sheet takes away material only partway through the thickness of the sheet. By use of a plotting for thelower side which includes the base of the disk, the chemical on thelower surface of the sheet takes away material on the outside of thedisk and in the center of the disk which is to receive the tube. Thechemical acting on the bottom of the sheet takes away material part waythrough the thickness of the sheet. Because of action from both the topand the bottom, the material on the outside of the disk and in thecenter of the disk which is to receive the tube is completely taken awayby the etching process through the entire thickness of the sheet. Asmall projection may be left on the outside of the disk during theetching process to prevent the disk from being dislodged from the sheet.

[0062] It will be appreciated by persons having ordinary skill in theart that variations on this manufacturing process and othermanufacturing processes are possible. For example, an implant made ofplastic may be manufactured by a suitable molding operation.

[0063] As will also be appreciated by persons having ordinary skill inthe art, the various embodiments of intraocular implants, deliverydevices, and methods for implantation described hereinabove are given byway of example only. Various changes, modifications and variations maybe applied to the described embodiments without departing from the scopeof the invention, defined by the appended claims.

What is claimed is:
 1. An intraocular implant for implantation in aneyeball comprising: a tube for implanting into the eyeball comprising aninlet end, an outlet end, and a tube passage extending between the inletend and the outlet end for permitting aqueous humor to flow out of theeyeball; and a flanged disk connected to the tube at the outlet end ofthe tube for placing on a surface of the eyeball; wherein the tubepassage has a cross-sectional area sufficiently small to inhibit theflow of aqueous humor through the tube passage when an intraocularpressure of the eyeball is below a threshold amount.
 2. An intraocularimplant according to claim 1 wherein the tube passage is cylindrical,and wherein a diameter of the tube passage is substantially smaller thana length of the tube passage.
 3. An intraocular implant according toclaim 2 wherein the diameter of the tube passage is about 300micrometers or less.
 4. An intraocular implant for implantation in aneyeball comprising: a tube for implanting into the eyeball comprising aninlet end with a beveled surface at the inlet end, an outlet end, and atube passage extending between the inlet end and the outlet end forpermitting aqueous humor to flow out of the eyeball; and a flanged diskconnected to the tube at the outlet end of the tube for placing on asurface of the eyeball; wherein the beveled surface at the inlet end ofthe tube lies in a first plane forming an angle with the longitudinalaxis of the tube and the flanged disk lies in a second plane which isangled opposite to the first plane.
 5. An intraocular implant forimplantation in an eyeball comprising: a tube for implanting into theeyeball comprising an inlet end, an outlet end, and a tube passageextending between the inlet end and the outlet end for permittingaqueous humor to flow out of the eyeball; and a flanged disk connectedto the tube at the outlet end of the tube for placing on a surface ofthe eyeball; wherein the tube has at least one circumferential holewhich opens into the tube passage proximate the inlet end of the tube.6. An intraocular implant for implantation in an eyeball comprising: atube for implanting into the eyeball comprising an inlet end, an outletend, and a tube passage extending between the inlet end and the outletend for permitting aqueous humor to flow out of the eyeball; and aflanged disk connected to the tube at the outlet end of the tube forplacing on a surface of the eyeball; wherein the flanged disk comprisesa base, an outer rim, and at least one inner upright, and wherein thebase and outer rim form a reservoir having a larger cross-sectional areathan the tube passage.
 7. An intraocular implant according to claim 6wherein at least one inner upright is curved to form an inner rimproximate an axial outlet opening of the tube and substantially boundingthe axial outlet opening of the tube, the flanged disk furthercomprising at least one passageway in the inner rim for enabling flow ofaqueous humor from the axial outlet opening through the passageway. 8.An intraocular implant according to claim 6 wherein the flanged disk hasan elliptical shape.
 9. An intraocular implant for implantation in aneyeball comprising: a tube for implanting into the eyeball comprising aninlet end, an outlet end, and a tube passage extending between the inletend and the outlet end for permitting aqueous humor to flow out of theeyeball; and a flanged disk connected to the tube at the outlet end ofthe tube for placing on a surface of the eyeball; wherein the implanthas at least one retention projection for anchoring the implant in theeyeball, said retention projection being extended outwardly when theimplant is implanted in the eyeball.
 10. An intraocular implantaccording to claim 9 wherein at least one retention projection isextended outwardly by an expansion tool when the implant is implanted inthe eyeball.
 11. An intraocular implant according to claim 9 wherein atleast one retention projection is constructed of a shape memory alloyand is extended outwardly when subjected to the heat of the eyeball whenthe implant is implanted in the eyeball.
 12. A method of regulating anintraocular pressure of an eyeball comprising the steps of: providing anintraocular implant comprising (a) a tube for implanting into theeyeball, said tube comprising an inlet end, an outlet end, and a tubepassage extending between the inlet end and the outlet end forpermitting aqueous humor to flow out of the eyeball, said tube passagehaving a cross-sectional area sufficiently small to inhibit the flow ofaqueous humor through the tube passage when an intraocular pressure ofthe eyeball is below a threshold amount, and (b) a flanged diskconnected to the tube at the outlet end of the tube for placing on asurface of the eyeball; and implanting the intraocular implant in theeyeball including implanting the tube into the eyeball and placing theflanged disk on a surface of the eyeball.
 13. A delivery device forimplanting an intraocular implant into an eyeball, the delivery devicecomprising: a handle; and a rodlike instrument; wherein the rodlikeinstrument comprises a tip for penetrating a tube passage of the implantand a retention mechanism for retaining the implant on the deliverydevice.
 14. A delivery device according to claim 13 wherein the rodlikeinstrument comprises a probe.
 15. A delivery device according to claim13 wherein the rodlike instrument comprises a needle.
 16. A deliverydevice according to claim 15 wherein the tip of the rodlike instrumentfor penetrating a cube passage of the implant comprises a plug insertedin a bore of the needle.
 17. A delivery device according to claim 13wherein the retention mechanism comprises an abutment surface forabutting a flanged disk of the implant, wherein the abutment surface hasan angle generally corresponding to an angle of the flanged disk.
 18. Amethod of implanting an intraocular implant into an eyeball comprisingthe steps of: attaching the implant to a delivery device; cutting a slitin a portion of the conjunctiva of the eyeball which normally lies at adistance away from an intended implantation site; placing the implant bythe delivery device through the slit in the conjunctiva; directing theimplant by the delivery device to the implantation site; inserting theimplant through the sclera at the implantation site; withdrawing thedelivery device; and allowing the slit in the conjunctiva to be lie atthe distance away from the implantation size.
 19. A method of implantingan intraocular implant according to claim 18 wherein the distancebetween the slit in the conjunctiva and the implantation site is about 5millimeters or more.
 20. A method of implanting an intraocular implantaccording to claim 18 wherein the slit has a length of about 2millimeters or less.
 21. A method of implanting an intraocular implantaccording to claim 18 wherein, in the step of inserting the implantthrough the sclera, the sclera is penetrated by a tip of the tube of theimplant.
 22. A method of implanting an intraocular implant according toclaim 18 wherein, in the step of inserting the implant through thesclera, the sclera is penetrated by a needle tip of the delivery device.23. A method of implanting an intraocular implant into an eyeballcomprising the steps of: attaching the implant to a delivery device;directing the implant by the delivery device to the implantation site;inserting the implant through the sclera at the implantation site suchthat a beveled surface at an inlet end of the implant faces away fromthe iris; and withdrawing the delivery device.
 24. A method ofimplanting an intraocular implant into an eyeball comprising the stepsof: attaching the implant to a delivery device; directing the implant bythe delivery device to the implantation site; inserting the implantthrough the sclera at the implantation site such that a marker isvisible upon penetration through the sclera; and withdrawing thedelivery device.
 25. A method of implanting an intraocular implantaccording to claim 24 wherein the marker comprises a circumferentialhole.
 26. A method of implanting an intraocular implant into an eyeballcomprising the steps of: attaching the implant to a delivery device;directing the implant by the delivery device to the implantation site;inserting the implant through the sclera at the implantation site;extending outwardly at least one retention projection for anchoring theimplant in the eyeball; and withdrawing the delivery device.
 27. Amethod of implanting an intraocular implant according to claim 26wherein, in the step of extending outwardly at least one retentionprojection, at least one retention projection is extended outwardly byan expansion tool when the implant is implanted in the eyeball.
 28. Amethod of implanting an intraocular implant according to claim 26wherein, in the step of extending outwardly at least one retentionprojection, at least one retention projection is extended outwardly bythe action of a shape memory alloy from which it is constructed whensubjected to the heat of the eyeball when the implant is implanted inthe eyeball.
 29. A method of implanting an intraocular implant into aneyeball comprising the steps of: attaching the implant to a deliverydevice comprising a handle and a rodlike instrument comprising a tip forpenetrating a tube passage of the implant and a retention mechanism forretaining the implant on the delivery device; directing the implant bythe delivery device to the implantation site; inserting the implantthrough the sclera at the implantation site; and withdrawing thedelivery device.
 30. A method of implanting an intraocular implantaccording to claim 29 wherein the retention mechanism comprises anabutment surface for abutting a flanged disk of the implant, wherein theabutment surface has an angle generally corresponding to an angle of theflanged disk.
 31. A method of implanting an intraocular implantaccording to claim 29 further comprising the step of vibrating thedelivery device during the step of inserting the implant through thesclera at the implantation site.